Programming Tips: Test Often

Learn to love your browser’s reload button. Whenever you make a change that might affect your web page, test immediately. Don’t make a whole bunch of changes before testing; if your web page no longer works, you won’t necessarily know which change caused it to fail. Write your programs a step at a time and test often.

Test things that you don’t even expect to happen: try to think up weird scenarios and come up with a means of testing what happens to your page under those scenarios. This will give you valuable information about what your code is really doing.

Also, make extensive use of the “window.alert()” function to let you know the value of variables at troublesome points.